This invention relates to apparatus for making microadjustments in general, and more particularly to an improved apparatus of this type, particularly useful in optical systems.
In copending U.S. patent application Ser. No. 339,860, filed Mar. 9, 1973 and assigned to the same assignee as the present invention, an optical projection and scanning apparatus is disclosed. The apparatus disclosed therein relates to photographic apparatus useful in the manufacture of what are referred to as integrated circuits. This apparatus along with other similar apparatus requires adjustment of optical devices over very small ranges, of the order of fractions of microns. In prior art arrangements, adjustments of the type needed, for example, adjustments of prisms, have been performed using either ordinary screw adjustment or differential type screw adjustments. These prior art methods of adjustment have a roughness of the order of 0.0001 inch or 2.5 microns and in many cases, suffer from lost motion of the order of a micron or greater.
In view of the requirement in various types of apparatus for adjustments in the range of less than a micron, the need for an improved apparatus for carrying out such an adjustment is evident.